What is Clenbuterol?

Clenbuterol is used by sufferers of breathing disorders, such as asthma, but is illegal to buy or sell without a prescription.

It has become a popular drug for bodybuilders looking to cut weight quickly – that is because it increases metabolism for those who take it.

Like Salbutemol, clenbuterol also works by dilating the bronchi and bronchioles, decreasing resistance in the respiratory airway and increasing airflow to the lungs, although its effects are more potent and longer lasting.

In the European Union, clenbuterol is not allowed to be given to any animals that will be consumed by humans, although those rules do not apply to countries outside of Europe.

It is on the WADA banned list.

Cyclist Alberto Contador (pictured) tested positive for the drug and was stripped of his 2010 Tour de France title as a result.

Mexican boxer Erik Morales was banned for two years after testing positive.

Earlier this year, British Olympic sprinter Nigel Levine was provisionally suspended after testing positive for the drug.

Following the revelation of the positive samples, Canelo switched his training camp to the USA and vowed to undergo additional testing.

Golovkin demanded that Alvarez takes a lie detector test and said: “Canelo’s team are using these drugs and everybody’s trying to pretend it’s not happening.”